Electrical accessory apparatus



July 23, 1935. s. w. EDLUND ELECTRICAL ACCESSORY APPARATUS Filed June 30, 1928 INVENTOR Sidney W Ed/qnd.

Y E N m U A Patented July 23, 1935 J UNITED STATES ATE F ELECTRICAL accnssonr APPARATUS Sidney w. naiunan uyn, N. Y. Application June so, 192s, seris1No. 289,375 7 9 Claims. (61.173-343) This invention relates to electrical accessory apparatus, and refers particularly to separable attachment plugs or parts thereof. It is well understood that the usual'separable attachment plug consists of a base having electrical con tacts therein, and a cap member carrying prongs which are introduced into'thetbase and movcd into engagement with the base contacts. It has been the recent practice in buildingconstruction to permanently install in the floor, orbase boards or walls; the equivalent of the base .of. such a plug. This permanent base, .=through practice, has oftentimes been termed, as'oclret. Herein, it

will be understood that the .term be employed to denote the regular base of a plug or the so-called permanent base. The bases for the plugs are sometimes located in positions not readily accessible, often being back of articles of furniture, etc., and for this reason, among others, it is usually difficult to insert the prongs of the cap intov the base, both by reason of its inaccessibility: as well as by reason of the fact that'in such places sufficient light is not usually available to see thebase properly; Y I

v cause plugs have thus far not been made with any'particular 'or improved construction which" would permit the prongs to be readily guided into the slots of the base when the person attempting the assembly bringstheprongs in contact with the free or exposed surface of the base. Attachment plugs now in use are of three gen- 1 eral typeaandwhen the base of any of these plugs cannot be clearly seenthe same difllculty of assembly exists- The first type is one inwhich the exposed surface of the baseris flat; hence the chance of getting the prongs in proper align-' ment' on the first attempt of assembly is very small.

even with this type, portions of the free surface are flat and consequently there is no assurance of proper guidance of the prongsinto the slots" once the two prongs engage any points of the free surface. The third type has the area of the surface immediately around theslots recessed or-hollowed out. This construction is of advan- 85 construction of the free surface and the 7 arbase will The difficult assembly has hitherto arisen be- The second type of plug has, provided a very small taper at the, edges of the slots, but.

rangement of the slots thereinpsc that the only requirement of the person assembling the cap with the base'is to bring both of the prongs into any contact with the free surface, and there'- after by a slight manipulation of theprongs have 5 them guided into the slots- Further and more specific objects, features and advantages will more clearly appearfrom the detailed description given below when taken in connection with the accompanying drawing 16 which forms'part of the specification, and which illustrates the preferred-embodiments of the invention.- r In the drawingFig. 1 is a perspective view of a plug embodying the invention with a prong- 15 carrying cap shown in relation thereto.

Fig. 2 is an elevational view of the plug with the end surface thereof in section.

Fig. 3 is a perspective view, similar to Fig. 1,

showing an arrangement of slots and prongs at 20 a 7. 30 A preferred embodiment of my invention is shown in Figs. 1 and 2 and comprises aplug'having abody portion. [0 of standard construction to be screwed'into'a socket.- This body portion is generally of insulating material and has a top 35 or free portion H of insulating material. This portion i I is provided with an end or free surface I! having prong-guiding slots. I3 and. therein. These slots are spaced apart and lead to the usual chambersbe'neath the free surface. Within the 40 chambers are disposed, in the usual manner, con tact members with which engagement is made by prongs i5 and i6 suitably carried byfa cap .member .H which is provided with a bore I! through which acabl'e, not shown, may pass.

7 Referring particularly to Figs. land 2, it will be seen that the free surface l2 has a generally concave curvature which begins at the very edge of the surface and slopes downwardly and in-.

wardly throughout toward the center adjacent 50 which the slots I3 and I! are located. There preferably is providedfat the centergaraised hump, theconstruction and function of which will be later described. Consequently. itwill be observed, there are no flat portions on this free. surface,

4 tially the same, except that the slots 24 and 25 1 Letters Patent,

between the prongs.

that the prongs upon a slight movement shall im mediately be guided into the slots. In some few,

and when a pair of prongs are brought anywhere into contact with this free surface and are both within the periphery'of the edge, they will be' guided to the'slots.

The construction of the hump preferably has a central upper edge or ridge is and lateral surfaces 20 and 2| sloping gradually therefrom in opposite directions toward the adjacent slots i3 and I. From Fig. 2 it will be seen that this ridge line i9 is preferably for a substantial part of its length one level with the edge of the main surface-'lLbut that at its ends and 23 theridge I9 is curved downwardly. The construction is such that where the main surface joins the ends I and sides of =the hump, smooth curves result. Preferably the distance between either slot and the nearest portion of the edge of the main surface is designed to be less than the distance between the slots. Also the distance between'the ridge is and the edge of the main surface along a line drawn. across the slots is preferably designed to be greater than the distance between. the slots and therefore greater than thedistance This construction-requires instances the manipulator of the. capmay accidently move one of the prongs over the edge of surface i2, and before proper assembly is accomplished this prong. must be returned. to the free.

surface I2. r

- In Figs. 3, 4 and 5 the construction is essenlong as the prongs are brought into contact with the main or free surface of the base the relative position of' the prongs .at the instant of contact is immaterial. The inward and downward curvature of the main surface will tend to keep the prongs within that area and then a slight turning movement of the prongs willcause them to slip downwardly along the above-mentioned surfaces and readily and upon the first turning thereof it is found that a prong has encountered the wrong slot, it

merely requires a half turnin either direction to bring the prongs into alignment withthepropen slots without removing them from contact with the surface. While there has been described in'detaila particular improvement and in respect to a preferred form thereof, it is understood that the invention is not to be llmited'to such details or form since many changes and modifications may be made and the invention may be embodied in widely different forms without departing from the spirit and scope in the broader aspects.

Hence it is desired to cover all modifications and forms coming within the language or scope of any one or more of the appended claims. What isv claimed aslnew and desired to' be secured by isz' 1. a base for the reception of an attachment cap, saidbase having its free surface provided with slots for the reception of prongs carried by flnd'the slots. If prongs disposed atright angles to each other are employed,

said cap and having each part of the entire area of said surface sloping downward toward one or the other of said slots.

2. A base for the reception of an attachment cap, said base having its free surface provided with'slots for the reception of prongs carried by said cap and having each part of the entire area of said surface sloping inwardly and downwardly from its outer edge, the distance between any slot and the nearest portion of the edge being less than the distance between the slots.

3. A basefor the reception of an attachment cap, said base having its free surface provided with slots for the reception of prongs carried by said cap and having each part of the entire area of said surface sloping inwardly and downward- -ly from its outer edge toward its center. and a prong-guiding partition extending across said of said surface sloping inwardly and downwardly from its-outer edge toward its center, a prongguiding partitionfextending partiaiiy across said surface betweenthe slots, the lateral surfaces of .said partition sloping toward the adjacent slots.

5. A basefor the reception of an attachment cap, said baseflhaving its free surface provided with slots for the reception of prongs carried by saidcap and having each part of the entire area of said surface sloping inwardly and downwardly from its outer edge toward its center, and a prong-guiding partition extending partially across said surface between the slots, the lateral surfaces of said partition sloping toward the ad- 'jacent slots, the ridge of said partition near its ends sloping downwardly toward the main surface.

6. A base, for the reception of an attachment cap, said base having its free surfaceprovided with slots for the reception of prongs carried by said cap and having each partof the entire area of said surface sloping inwardly and downwardly from its outer edgetoward its center, and a prong-guiding partition extending part of the length across'saidsurface between the slots, the

lateral surfaces of saidpartition M09 8 toward the adjacent slots, the ridge. of said partition near its ends sloping downwardly toward the main surface, the center-portion of said ridge being substantially level with the edge of the main surface. w 1

-7. A base for the'reception of an attachment cap, said base having itsfree'surface provided with slots for theireception of prom carried by said cap and having each part of the entire area of said surface sloping inwardly and downwardly from its outer edge toward its center, and a prong-guiding partition extending across-said surface between the slots, the lateral surfaces of said partition sloping toward the adjacent slots,the ridge of said partition near its ends sloping downwardly toward the main surface, the'center portion of said ridge being substantially level withthe edge of the main surface, the lateral and end surfaces of said partition and the main surface of the plug joining in smooth curves a 8. A base for the reception of an attachment cap, said base having its free surface provided with slots for the reception of prongs carried by said cap and having each part of the entire area of said surface sloping inwardly anddownwardfl 1y from its outer edge toward its center, and a prong-guiding partition extending partially across said surface between the slots, the lateral surfaces of said partition sloping toward the ad- Jacent slots, the ridge of said partition near its ends sloping downwardly toward the main surface, the lateral and end surfaces of said part1 tion and the main surface of the base meeting in smooth curves, the distance between each slot and the nearest portion of the edge of the plug being less than the distance between said slots.

9. An attachment plug comprising a base portion having a free surface with prong-receiving slots therein, the entire area of said surface slop ing inwardly and downwardly from its outer edge toward its center, and a prong-guiding partition extending across said surface between the slots, the lateral surfaces of said'partition sloping toward the adjacent slots, the ridge of said partition near its ends sloping downwardly toward the main surface, the center portion of said ridge being substantially level with the edge of the main surface, the lateral and end surfaces of said partition and the main surface of the base meeting in smooth curves, the distance between each slot and the nearest portion of the edge of the plug being less than the distance between slots, the distance between the ridge of said partiticn and the edge of the base along a line across the slot being greater than the distance between slots.

SIDNEY W. EDLUND. 

